On Sun, 2016-09-25 at 22:35 +1000, Anton Blanchard wrote: > From: Anton Blanchard <an...@samba.org> > > POWER8 handles unaligned accesses in little endian mode, but commit > 0b5e6661ac69 ("powerpc: Don't set HAVE_EFFICIENT_UNALIGNED_ACCESS on > little endian builds") disabled it for all. > > The issue with unaligned little endian accesses is specific to > POWER7, > so update the Kconfig check to match. Using the stat() testcase from > commit a75c380c7129 ("powerpc: Enable DCACHE_WORD_ACCESS on > ppc64le"), > performance improves 15% on POWER8.
Hrm.. this should really be a runtime switch... > Signed-off-by: Anton Blanchard <an...@samba.org> > --- > arch/powerpc/Kconfig | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig > index 0a70c86..04c447d 100644 > --- a/arch/powerpc/Kconfig > +++ b/arch/powerpc/Kconfig > @@ -96,7 +96,7 @@ config PPC > select VIRT_TO_BUS if !PPC64 > select HAVE_IDE > select HAVE_IOREMAP_PROT > - select HAVE_EFFICIENT_UNALIGNED_ACCESS if !CPU_LITTLE_ENDIAN > + select HAVE_EFFICIENT_UNALIGNED_ACCESS if > !(CPU_LITTLE_ENDIAN && POWER7_CPU) > select HAVE_KPROBES > select HAVE_ARCH_KGDB > select HAVE_KRETPROBES